

/* Copyright 1998 by the Massachusetts Institute of Technology.
 *
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for any purpose and without
 * fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting
 * documentation, and that the name of M.I.T. not be used in
 * advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is"
 * without express or implied warranty.
 */

#include "ares_setup.h"

#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif

#include "ares.h"
#include "ares_private.h"

#ifndef HAVE_WRITEV
ssize_t ares_writev(ares_socket_t s, const struct iovec* iov, int iovcnt)
{
    char *buffer, *bp;
    int i;
    size_t bytes = 0;
    ssize_t result;

    /* Validate iovcnt */
    if (iovcnt <= 0) {
        SET_ERRNO(EINVAL);
        return (-1);
    }

    /* Validate and find the sum of the iov_len values in the iov array */
    for (i = 0; i < iovcnt; i++) {
        if (iov[i].iov_len > INT_MAX - bytes) {
            SET_ERRNO(EINVAL);
            return (-1);
        }
        bytes += iov[i].iov_len;
    }

    if (bytes == 0)
        return (0);

    /* Allocate a temporary buffer to hold the data */
    buffer = ares_malloc(bytes);
    if (!buffer) {
        SET_ERRNO(ENOMEM);
        return (-1);
    }

    /* Copy the data into buffer */
    for (bp = buffer, i = 0; i < iovcnt; ++i) {
        memcpy(bp, iov[i].iov_base, iov[i].iov_len);
        bp += iov[i].iov_len;
    }

    /* Send buffer contents */
    result = swrite(s, buffer, bytes);

    ares_free(buffer);

    return (result);
}
#endif
